Adjustable expanding center.



W. L. KEEFER.

ADJUSTABLE EXPANDING CENTER.

APPLICATION msu APR. 27. 191s.'

2 SHEETS-SHEET l.

. Inventor I w. L. KEEFER.

l ADJUSTABLE EXFANDING CENTER. y APPL|AT|oN- r||.'o APn.21,191e.

' Patented Man-20,1917,

s2/@unam Wai! L;

. miente'.

VALTER.` LfKEEFER, OF FITCHBUBG, MASSACHUSETTS.

ADJUSTABLE V i Specification of Letters Patent.

EXPANDING CENT: an.

patented nur. 2o, 1917.

application ined Apru 27, 191e. serial No. )3,921

T0 all whomt may concern.'

Be it known that I, VALTEP. L. KEEFER, a citizen of the UnitedA Stated residing at Fitchburg, in the county of Worcester and State of l\lassachusetts1 have invented certainbnew .and useful Improvements in Adjustable EX\panding Centers: and I do declare the following to be a full, clear. and ex act description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

AThis invention relates to tools used by machinists, and otherworkmen for determining the centers of the circule r recesses, openings, or bores through metal castings, or other objects. l

The primary object ofthe invention is to overcome the heretofore waste of time in determining in a very inaccurate way the exact center of such an opening or bore in a casting, by the provision of an adjustable eX- panding tool or center, the centering pin of which is designed to'be normally centrally arranged with respect to a pluralityr of arms adapted to engage the interior sides of the openingmor'bore in the casting. The point so determined may be used as the centerof a circle to be scribed on-the casting concentric to the opening or bore therein, or to be used as a.' fixed. point from which to take measurements of any desired nature.

A, further object of the invention is to provide adevice of this character wherein the centering pin is adjustably' mounted with respect to the central axis of the device in order that it may be moved out ofits normal position so that a circle may be scribed or measurements taken from a point eccentric to the longitudinal axis of the opening or bore in the casting. 'A stillfurther oJject of the invention is to providea device of this character which will be of simple` comparatively strong. durable and inexpensive construction. etiicient and reliable in operation. and well adapted to the purpose for which it is designed.

"With these and other objects inA view. the invention 'consists of certain novel features of construction. and the combination and arrangement of parts as will be hereinafter fully described and claimed.

\ The accompanying drawings. forming part of the specification, illustrate one 'way in lwhich the invention may be constructed. and vwherein Figure 1 is a top plan View of a device constructed ir accordance with this invention@ 4 'F ig. 2 is a side elevation of the same showing the applic ltion thereof to the bore or recess in 'a metal cast-ing; i

Fig. 3 is a sectional view taken on the plane of the line 3 3 of Fig. l;

- Fig. 4 is a top plan view of the device with the top plate removed:

Fig. 5 is asimilar view of the device with the casing removed from the base member showing the concentrically mounted cam carrying plata;

lFig. 6 is a similar view of the central portion of the de vice showing the centering pin in a position eccentric tothe longitudinal axis of the device;

Fig. 7 is a pers )ective view of the disassembled elenic nts orming the centering pin; and,

Fig. 8 is a similar view of the locking dog and handle member therefor.

Similar reference characters designate like parts throughout the several views.`

Referring more particularly to the draw.

ings, the ref( rence numeral 1 designates a circular or cylindrical casing having a 'cenf trally arranged circular opening 2 in its closed end. the other Vend being open.. and a plurality of notches 3 in its sides.` lSecured to the open end of the casing 1 by suitable screws 4 is a base member, here shown in the form o::` a circular plate.

This plate 5 is provided 'with a cent-rally arranged ope ning from which radiates a plurality of rectangular channels 7. These channels T ha ve their outer ends disposed in alinement wii h the aforesaid notches 3. and have slidabl;y mounted therein a plurality of radially extending arms S. the purpose of which will bt hereinafter described. The reference numeral 9 designates a circular memberl or plate having a centrally arranged ape Lture 10 therein through which extends a shaft 11. the inner end of which is provided with a head 1Q. This plate 9 is revolubly mounted concentricallv with -re-f' spec-t to the aforesaid plate and is provided u-ith a plurality of cams. here shown in the form cf scroll devices or slots'l. that arcuate slots extending :spirallv from the central axis 'of the plate.V Extendinglater-na allv from the inner sides of the arms att-he inner ends tliereof are suitable pins ll. said pins, being received in the scroll slots 13. whereupon when the plate 9 is revolved, th:

` der the tension of the arms 8 will be moved outwardly or inwardly according tothe direction in which the plate 9 is turned, the outer ends of said arms always moving concentrically relatively to the central axis of these plates.

The plate 9 is provided on its inner side with a suitable catch in the form of a radiallv slidable dog 15 the latter being provided with a pair o inner end which straddle-the head 12 of the shaft 11, while the'outer end of the dog 15 is bentlaterally at right angles and twisted for a purpose to be described. Extendin lateral y from the plate 9 is a pair of space stops ory pins 17, between which the outer end of the dog 15 is disposed, thereby preventingthe latter from swinging aroundtlie head 12. Fixed at one end to one ofthe pins 17 is an arcuate resilient spring 18, the

other end of which is hooked around or otherwise secured to the outer end of the dog 1 5. It is to be understood that by this construction, thedog 15 is normally forced outwardly into engagement with suitable ratchet teeth 19 arranged on the inner side of the casing 1. These teeth are here shown formed on the outer edge of an arcuate'slot' 20 arranged in the end of the casing. The 1aterally bent outer end'of the dog 15 extendsthrough this arcuate slot 20, and com'- 'prises, in eii'ect, a thumb piece or handle 21 to be engaged when it is desired to o crate the dog and move the plate 9- within the casing 1.V

Extending through the opening 2 of the casing is a a pin 22, theinner end of which is rovided with a disk-like head 23 between'w ich and.

the inner side of the end of the casin is disposed aspring washer 24. This hea 23 unwasher21bears firmly against the head 12 shaft 11, thus yieldably'clamping'said centering pin in place so as to allow the saine to be positioned. either concentric or eccentric v to thece'ntral axis of the casing'. The free 4 centrally' end ofthe pin arranged recess. 25 which. is adapted to receive the pivot point of a compass when it is being usedas a center when scribing a circle aroundthe casting. or whenit is being used as a point from which measurements may be taken. the purposes of which will skilled in the art.

be apparent to those Secured by suitable screws 26 to the end of the casing 1 a circular plate 275 the latter having a centrally arranged opening 2S 'and an arcuate slot 29 disposed respectively1 in -alineinent with the ing 2 and slot 2O in the casing. Extending outwardly from the edges of this are fingers 30, the outer ends of w ich are disposed in planes beyond the outer limit of the arms 8, for a purpose to be described.

-. the drawin spaced arms 16 at its centering member in the form of the Pin.

-this can' be accurat ly deter of the aforementioned` 22 is provided with -a smallv opening in a 'aforesaid openlate 2T' .connection with ings. vthe construction and advantages of the is shown ini igs.. as bein tional meta asting bore A extendin therethroug the fingers 30 contacting with tl el. end off= the casting and preventing the cui" e device from being inserted too far into the opening while the arms 8 are en aged atA their outer ends with the sides of the bore. if It is of course to be understood that these farms 'are moved or brought into firm contact with the bore' by turning the plate 9 in the ma iler' herleinbefore described. The og 15, er the tension of its spring, en I ges thev eth 19 and normally retains the arms iin thir extendedpositions, and thus locks the device in place. The device bein thus lq'cked in thelbore, and it is known tiat Ithe1centeiin, f= in 22 2 ,and 3 of The devic the exact vice. said in willcoincii'e wiith5 center of tie bore.l anl measl reinents may be taken from the poi t or reces-S125 thereof, orcircles may' be scribed th reffrom concentricto the bore of the castiflr.' Iif, however, it is desired to scribe circ'l s -fi m a point eccentric to the central alxfi o|`f he bore, it is only necessary to Inovix ie Ice tering pin 22 outof its known ce te position. This inav be readilv don i the' ietei'nbefore des 1 i scribed manner, ow ne to the act that 1t is adjustably mounted with respect to the shaft 11. The spring washer 21 is always under sutlicient'tension to canse the head 230i the p'in to firmly engage the head 12 of the shaft 11 and prevent accidental displacement of Tie pin 22 may bef applroiniately centered by eye-sight; as even i very small the opening 2 will e not" amount of eccentritgty betvfvleerif the in and b e. l owever, Titled b v scr b.- ing on the end of the casting gat;90.- d egr es apart, four arcs of a'circle. of fa great r: adius than the bore of the latter. T-.he arcs casting. If they are iiotutieprthe pin is eccentrically positioned` tlie 'amount of such eccentricity being numerically equal to onehalf the diti'erence letweei the distances of two diametri'cally opposite arcs from the bore. 'hen this has been deteriziined, the pin may be moved in tl e proper{ jlirectimi this amount. It is then centered inthe same manner with respect to metrically opposite arcs.

By taking similar measurements with. a

should be equi-distant lroin-fhe bore of the,

moved eccentrically the exac la nennt. iter' tion. From the foregoing description. taken in the accompanying drawinvention willl he understood without a more extended explanation.

pfliiI iedl to, a Couvenl avi'ng n opening or` 'the otherwwo cliziaV ios vided with means for moving said armsv concentrically to the central axis of the same, a dog slidably mounted on said' member, a spring fixedly mounted within said casin and operativel connected with said dog or forcing the atter outwardly, and ratchet teeth arranged on the inner fside'of and engaged by \said dog for llocking said member against movement.

mounted Within sai 2. A devicev of the class described comprising a casing, a plurality of arms extendlng from said casin a,1 member revolubly casing and provided with means folxmovingv said alms concentrically to the central axis of the same; a dog radial] yslidable on said member, a spring fix y` mounted within said casing and operatively connected with said dog7 for forcing th latter outwardly, ratchet teeth arranged n the inner side of said casin and engaged by saiddog for locking sai member agaixist movement, said casing bei ing provided -With an arcuate slot in one of its ends, and a handle extending laterally from the outer end of said dog for operating the same and for revolving 'said member within said casing.

- 3. A Ydevice of :he class described comprising'a casing, a plurality of arms pro- ]ecting from said casing, means mounted within said casing for moving said 4arms radially and holding them'concentric `to the 'central axis of the same, and a eente member adjustably mounted within sai casing with respect to the central axis there-- of'and having me: ns for frictionally holding it in its' adjustrdposition.v

4. A device of the class described comprising a casing having a-eentral opening at-one end thereof, a plurality of arms projecting radially from said casing, means mounted Within said casing for moving said arms radially and holding them concentricto the central axis of the same, a centering pin extendin longiI tudinally with respect to -said casing, t e inrer end of said pin being disposed within the latter, the outer end of said pin 'extending through said o 'ng to. the exterior of sale casing,'and a ead car` ried by the inner end of said pin yieldably clamped within said casing to allow said `pin to be moved eccentl ically with respect to the central axis of the saine.

In testimony whereof I have hereunto set my hand in presenc e of two subscribing witnesses. WALTER L. KEEFER. Witnesses:

`WILLIAM P. Cnam-zar, `GEORGE E. BROWN. 

